The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Toy gun, garden gnome used in robbery

Thieves armed with a toy gun used a garden gnome to smash a car's windows before bashing the driver and robbing him in Sydney's west.

The 33-year-old man was sitting alone in his car in Smithfield on Saturday morning when the four-man gang smashed his windows with the gnome and punched him several times in the face before one of the men produced a black-coloured gun.

He was punched again and robbed of his cash before the men took off on foot. A garden gnome and a black toy pistol were found nearby, police say. Anyone with information is urged to call Crimestoppers.